In the magnet wire industry, it is common practice to supply wire wound on molded plastic spools having a barrel with two end flanges. Such plastic spools loaded with substantial weights of wire are ordinarily shipped, stored and handled with one end flange resting on a supportive surface. To permit lifting and transporting of this type of spool with a hoist, it is known to provide the spool with a rigid bar or rod disposed along the longitudinal axis of the spool and having at its upper end a ring or eye adapted to receive a suitable hook. Examples of spools of this type of lifting structure are shown in Kovaleski U.S. Pat. No. 4,140,289 and the O'Connor et al U.S. Pat. No. 4,253,569. It is also known, as shown by the Donovan U.S. Pat. No. 2,944,759, to secure a plate-like lifting handle to a wire-carrying drum transversely of the drum's longitudinal axis. Many wire users, however, prefer smaller spools which weigh about 35 kilograms when loaded and thus can be manually lifted and carried about without use of a hoist. To facilitate manual lifting of such spools, it would be desirable to provide the spools with lifting handles which could be grasped by human hands.
As shown by the Brookhart U.S. Pat. No. 1,408,261 and the Alten U.S. Pat. No. 2,508,809, it is old to provide a spool or reel with a manually grippable handle for lifting and carrying purposes. The Lane et al U.S. Pat. No. 3,406,817 discloses a molded plastic container for magnet wire which is formed with an integral lifting handle extending transversely across the end of a tubular inner wall. The employment of such a single lifting handle with a spool bearing a substantial weight such as 35 kilograms of wire is disadvantageous since it can be conveniently grasped with only one hand. A single plastic handle of the type disclosed in U.S. Pat. No. 3,406,817 would also tend to fracture when used to lift a spool loaded with more than 30 kilograms of wire.
A further disadvantage of prior lifting handle arrangements for wire spools is that the handle extends transversely across the longitudinal axis of the spool. Wire is commonly wound onto and dispensed from spools by processing machines having a spindle inserted into centrally located bushing portions of the spools. Accordingly, a spool having a handle extending transversely across its longitudinal axis could not be utilized with all customary types of wire processing machines.